2,058 research outputs found
Canonically quantized soliton in the bound state approach to heavy baryons in the Skyrme model
The bound state extension of Skyrme's topological soliton model for the heavy
baryons is quantized canonically in arbitrary reducible representations of the
SU(3) flavor group. The canonical quantization leads to an additional negative
mass term, which stabilizes the quantized soliton solution. The heavy flavor
meson in the field of the soliton is treated with semiclassical quantization.
The representation dependence of the calculated spectra for the strange, charm
and bottom baryons is explored and compared to the extant empirical spectra.Comment: 13 pages, 8 table
Quantum Black Holes
Static solutions of large- quantum dilaton gravity in dimensions are
analyzed and found to exhibit some unusual behavior. As expected from previous
work, infinite-mass solutions are found describing a black hole in equilibrium
with a bath of Hawking radiation. Surprisingly, the finite mass solutions are
found to approach zero coupling both at the horizon and spatial infinity, with
a ``bounce'' off of strong coupling in between. Several new zero mass solutions
-- candidate quantum vacua -- are also described.Comment: 14 pages + 6 figure
Effect of phosphorus level and phytase inclusion on the performance, bone mineral concentration, apparent nutrient digestibility, and on mineral and nitrogen utilisation in finisher pigs.
peer-reviewedFunding for this research was provided under the National Development Plan, through the Research Stimulus Fund, administered by the Irish Department of Agriculture, Fisheries and Food.Two experiments were conducted to investigate the interaction between dietary P
concentration and phytase (PHY) inclusion in the diet of finisher pigs. In Experiment
1, the growth performance and bone analysis experiment, pigs (6 replicate groups of
14 pigs each per treatment; initial body weight (BW) = 45.2 kg) were allocated to one
of six dietary treatments (for 74 days) in a 3 × 2 factorial arrangement: T1 – available
P in the diet = 1.5 g/kg; T2 = T1 with 500 units of phytase (FTU)/kg; T3 – available
P = 2.0 g/kg; T4 = T3 with 500 FTU/kg; T5 – available P = 2.5 g/kg; T6 = T5 with 500
FTU/kg. Experiment 2 consisted of a digestibility and a P, Ca and N balance study, and
pigs (6 per treatment; initial BW = 67.3 kg) were offered identical diets to those offered
in Experiment 1. There was an interaction between dietary P level and PHY inclusion for
average daily gain (ADG) and carcass weight (CW; P < 0.05) in Experiment 1. Pigs offered
the low P diet supplemented with PHY had a higher ADG and CW than pigs offered the
non-PHY, low P diet. However, there was no effect (P > 0.05) of PHY inclusion on ADG or
CW with the medium or high P diets. Higher concentrations of ash, P and Ca in bone were
noted in pigs offered the medium and high P diets (P < 0.001) and PHY (P < 0.01) diets
when compared to pigs offered the low P without PHY. Pigs offered diets supplemented
with PHY had lower faecal P output (P < 0.01) and a higher P digestibility (P < 0.001)
and P retention (P < 0.05) than pigs offered diets without added PHY. In conclusion,
supplementation of a low-P finisher diet with PHY resulted in pigs that had a similar carcass
weight, but weaker bones than pigs offered a medium or high P diet.Department of Agriculture, Food and the Marin
Classical and quantum geometrodynamics of 2d vacuum dilatonic black holes
We perform a canonical analysis of the system of 2d vacuum dilatonic black
holes. Our basic variables are closely tied to the spacetime geometry and we do
not make the field redefinitions which have been made by other authors. We
present a careful discssion of asymptotics in this canonical formalism.
Canonical transformations are made to variables which (on shell) have a clear
spacetime significance. We are able to deduce the location of the horizon on
the spatial slice (on shell) from the vanishing of a combination of canonical
data. The constraints dramatically simplify in terms of the new canonical
variables and quantization is easy. The physical interpretation of the variable
conjugate to the ADM mass is clarified. This work closely parallels that done
by Kucha{\v r} for the vacuum Schwarzschild black holes and is a starting point
for a similar analysis, now in progress, for the case of a massless scalar
field conformally coupled to a 2d dilatonic black hole.Comment: 21 pages, latex fil
S-Wave Scattering of Charged Fermions by a Magnetic Black Hole
We argue that, classically, -wave electrons incident on a magnetically
charged black hole are swallowed with probability one: the reflection
coefficient vanishes. However, quantum effects can lead to both electromagnetic
and gravitational backscattering. We show that, for the case of extremal,
magnetically charged, dilatonic black holes and a single flavor of low-energy
charged particles, this backscattering is described by a perturbatively
computable and unitary -matrix, and that the Hawking radiation in these
modes is suppressed near extremality. The interesting and much more difficult
case of several flavors is also discussed.Comment: 9p
The application of low crude protein wheat-soyabean diets to growing and finishing pigs: 2. The effects on nutrient digestibility, nitrogen excretion, faecal volatile fatty acid concentration and ammonia emission from boars
peer-reviewedThis study received financial support from Telltech Ltd. (Wicklow, Ireland) and Enterprise Ireland (Dublin, Ireland).Diets containing 132, 152, 183 and 206 g/kg crude protein (CP) were fed to growing and
finishing boars to evaluate the effect on nutrient digestibility, N balance, faecal volatile
fatty acids (VFA) and ammonia-N (NH3–N) emission. Dietary CP concentration was
adjusted by altering the ratio of wheat:soyabean meal. Lysine, threonine, tryptophan
and total sulphur-containing amino acids were included in all diets at concentrations
equivalent to that in the highest CP diet. All diets were formulated to provide 9.7 MJ/kg
of net energy. Urine and faeces were collected from 16 boars (4 boars per treatment)
housed in metabolism crates. Collections were performed at 72, 80 and 87 kg live weight.
NH3–N emission was measured over 10 days using a laboratory scale procedure.
Reducing the concentration of dietary CP decreased N intake (linear, P < 0.01), the
excretion of urinary N, ammoniacal N and total N (linear, P < 0.001; cubic, P < 0.001)
and the emission of NH3–N (linear, P < 0.001; cubic, P < 0.01). Total N excretion and
NH3–N emission decreased 8.7% and 10.1% per 10 g/kg reduction in dietary CP
concentration between 205.6 and 131.9 g/kg, respectively. There was no interaction
between dietary CP concentration and collection period. N balance differed between the collection periods and less NH3–N was emitted at 87 kg than at 72 kg. Decreasing
dietary CP reduced faecal VFA concentration (linear, P < 0.05) and the molar proportions
of acetic and butyric acids (quadratic, P < 0.01).Enterprise Irelan
Canonical Equivalence of a Generic 2D Dilaton Gravity Model and a Bosonic String Theory
We show that a canonical tranformation converts, up to a boundary term, a
generic 2d dilaton gravity model into a bosonic string theory with a
Minkowskian target space.Comment: LaTeX file, 9 pages, no figure
Baryons Containing a Heavy Quark as Solitons
The possibility of interpreting baryons containing a single heavy quark as
bound states of solitons (that arise in the nonlinear sigma model) and heavy
mesons is explored. Particular attention is paid to the parity of the bound
states and to the role of heavy quark symmetry.Comment: 15 pages, uses phyzzx.tex and tables.tex, REVISED VERSION: Some of
the results have changed because of a crucial minus sign, CALT-68-1783 and
UCSD/PTH 92-1
Exact C=1 Boundary Conformal Field Theories
We present a solution of the problem of a free massless scalar field on the
half line interacting through a periodic potential on the boundary. For a
critical value of the period, this system is a conformal field theory with a
non-trivial and explicitly calculable S-matrix for scattering from the
boundary. Unlike all other exactly solvable conformal field theories, it is
non-rational ({\it i.e.} has infinitely many primary fields). It describes the
critical behavior of a number of condensed matter systems, including
dissipative quantum mechanics and of barriers in ``quantum wires''.Comment: harvmac, 10 pages, PUPT-1432/IASSNS-HEP-93/7
On Topological Susceptibility, Vacuum Energy and Theta Dependence in Gluodynamics
We suggest that the topological susceptibility in gluodynamics can be found
in terms of the gluon condensate using renormalizability and heavy fermion
representation of the anomaly. Analogous relations can be also obtained for
other zero momentum correlation functions involving the topological density
operator. Using these relations, we find the theta dependence of the
condensates , and of the partition function for small theta
and an arbitrary number of colors.Comment: Details of the derivation are clarified, changes in discussions, new
references are adde
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